青龙河底栖无脊椎动物群落结构及其水质评价

本文论述了青龙河底栖生物种类、数量、分布和结构等特点及其与环境因子间的关系。应用Beck、Gleason、Shannon、Simpson等生物指数对水质状况进行评价。结果表明青龙河除个别断面受污染外,大部分河段属尚清洁水。     

中华眼镜蛇蛇毒因子(CVF)对补体系统的作用及与人补作C_3和其他蛇毒抗原性关系

中华眼镜蛇蛇毒经DEAE-Sepharose CL-6B。HPLC等多次柱层析分离出有抗补体及溶血活性的眼镜蛇蛇毒因子(Cobra venom factor,CVF),纯化后的CVF在聚丙烯酰胺凝胶电泳图谱上呈单一区带,分子量为225000—230000,等电点为6.20。用二硫苏糖醇还原经SDS-聚丙烯酰胺凝胶电泳得三类亚基,其分子量总和为237,000。 体外抗补体及溶血试验表明,CVF的作用是通过补体旁路途经使总补体活力下降。双向免疫电泳鉴定,发现CVF与人血清作用后,其中补体成分C_3分子的抗原性发生改变,则表明CVF的作用是通过激活补体成分C_3而发挥的。给豚鼠腹腔注射CVF(0.15ug/g体重)后,其血清总补体水平下降到正常值的3％以下,7天后回升,13天后恢复到正常水平。 单相免疫电泳表明,CVF与人补体C_3抗血清间无任何交叉免疫反应,但人血清与CVF抗血清间有微弱的免疫沉淀反应。另外,CVF的氨基酸组成与人补体C_3也较为相似。鉴定还表明眼镜蛇科中四种蛇毒与CVF抗血清有强烈的免疫沉淀反应,蝰蛇毒及海蛇毒也有免疫沉淀反应,但只有眼镜蛇毒具有抗补体活性。     

T3 reverses the changes in met-enkephalin and beta-endorphin contents in the anterior lobe, but not the neuro-intermediate lobe of the pituitary of rats rendered hypothyroid by PTU-treatment

The changes in met-enkephalin and beta-endorphin contents in the pituitary in PTU-induced hypothyroidism were studied in the rat. After 2 weeks of PTU-treatment, both IR-met-enkephalin and IR-beta-endorphin contents in the pituitary were significantly reduced. Gel filtration chromatography followed by radioimmunoassay showed that the immunoactivities in the peaks of precursors, met-enkephalin, beta-lipotropin and beta-endorphin were all lower in the pituitaries from the PTU-treated rats. In another experiment, some of the PTU-treated rats were injected daily with 500 micrograms T3/kg b.w. In the hypothyroid rats, IR-met-enkephalin and IR-beta-endorphin contents were decreased in both the anterior and neurointermediate lobes. Only the changes in the anterior lobe were reversed by T3 treatment. In conclusion, while the effects on the anterior lobe are probably due to a deficiency in thyroid hormones, the mechanism for the decrease of opioid peptide contents in the neurointermediate lobe is still unclear.     

The functional cell surface glycoprotein CD9 is distinguished by being the major fatty acid acylated and a major iodinated cell-surface component of the human platelet

We showed that a 22 kDa protein (which comigrated with the leukocyte differentiation antigen CD9 as determined by immunoblotting with the platelet-activating mAb 50H.19) is a major iodinated component of the platelet surface. The iodinated protein was identified as CD9 by limited proteolysis analysis. The major acylated protein in platelets incubated with [3H]palmitic acid also had a mobility of 22 kDa. The radiolabelled fatty acid in CD9 appears to be ester bonded, as it is removed by treatment with hydroxylamine. Non-enzymatic ligation of the fatty acid is not involved. Since platelets lack protein synthetic capacity, the palmitolation of a surface protein indicates the existence of a plasma-membrane located transacylase which functions independently of protein synthesis. Limited proteolysis analysis of the palmitylated protein obtained by immunoprecipitation with mAb 50H.19 confirmed its identity as CD9. An additional novel minor component of 27 kDa was detected in platelets by immunoprecipitation of 125I-surface-labelled, or [3H]palmitic acid-labelled protein, and by immunoblotting with mAb 50H.19. The analogous cleavage patterns obtained by the limited proteolysis analysis of the 22, 24 and 27 kDa glycoproteins suggest that they may be differently modified variants of a single polypeptide.     

Establishment and characterization of murine macrophage hybrids

Proteose peptone-induced peritoneal macrophages from CBA/J (H-2k) mice have been fused to a hypoxanthine phosphoribosyltransferase-negative variant of the P388D1 (H-2d) murine macrophage cell line. Six hybrid clones were isolated following HAT selection and further characterized. Five of the six clones express class I antigens of both parental haplotypes by microelisa and by flow cytometric analysis. Class II antigen expression of both haplotypes was apparent following a 72-hr incubation of the hybrids with concanavalin A-stimulated rat spleen cell supernatant. However, I-Ad was expressed in all hybrids to a greater extent than I-Ak. Three clones with the highest level of I-Ak expression, E5, C2, and C4, were capable of antigen presentation to the I-Ak-restricted T-cell line, D10.G4.1. LPS induction of the hybrids resulted in a 2- to 15-fold increase in the amount of IL-1 produced relative to the P388D1 parent. Finally, in distinction to P388D1, all hybrids demonstrated increased Fc-mediated erythrophagocytosis of chromium-labeled antibody-coated erythrocytes. These murine macrophage hybrids appear stable and should serve as useful models in understanding the regulation of macrophage function.     

Modulation of reconstituted cholesterol 7 alpha-hydroxylase by phosphatase and protein kinase

Cholesterol 7 alpha-hydroxylase activity was completely inhibited by incubation with alkaline phosphatase in a reconstituted enzyme system containing a cytochrome P-450, NADPH-cytochrome P-450 reductase and phospholipid. On the other hand, cAMP-dependent protein kinase stimulated cholesterol 7 alpha-hydroxylase activity by 2.5-fold. The modulation of cholesterol 7 alpha-hydroxylase activity was dependent on the amount of phosphatase or kinase added. The phosphatase inhibited enzyme activity was partially reversed by the treatment with protein kinase. These experiments indicate that the reconstituted cholesterol 7 alpha-hydroxylase activity is reversibly regulated by phosphorylation/dephosphorylation mechanism.     

The relative cytotoxicity and mutagenicity of cyclobutane pyrimidine dimers and (6-4) photoproducts in Escherichia coli cells

In order to calculate the relative cytotoxicity and mutagenicity of (5-6) cyclobutane pyrimidine dimers and (6-4) photoproducts, we have measured survival and mutation induction in UV-irradiated excision-deficient E. coli uvrA cells, with or without complete photoreactivation of the (5-6) dimers. Radioimmunoassays with specificity for (5-6) dimers or (6-4) photoproducts have shown that maximum photoreactivation eliminates all of the (5-6) dimers produced up to 10 Jm-2 254-nm light, while it has no effect on (6-4) photoproducts. These results were confirmed by measuring the frequency of T4 endonuclease V-sensitive sites. Based on the best fit equations for survival and mutation induction, we have found that the calculated cytotoxicity of (6-4) photoproducts is similar to that of (5-6) dimers; however, the former is much more mutagenic than the latter.     

斯氏狸殖吸虫螺类宿主新记录:洪山拟钉螺新种记述

本文报道斯氏狸殖吸虫新的螺类宿主——洪山拟钉螺Tricula hongshanensis sp. nov.的特点:螺壳较宽而短,体螺层较高大,壳口上缘成锐角,触角伸展时较长,收缩吋有环状皱褶,雄性阴茎较粗短,末端钝圆,齿舌公式不同于其它拟钉螺。     

血友病患者血清中淋巴腺病病毒/人T细胞Ⅲ型病毒抗体检测

对浙江省1982～1984年注射了美国产浓缩Ⅶ因子制剂的18例血友病患者,用酶联免疫吸附法(ELTSA)检测了血清中淋巴腺病病毒/人T细胞Ⅲ型病毒(LAV/HTLV-Ⅲ)抗体,发现4例阳性,并经免疫荧光试验和Western印迹法证实。2例应用了国产浓缩Ⅷ因子者抗体阴性。一例从美国来华旅游死于艾滋病者,LAV/HTLV-Ⅲ抗体阳性。本研究证明,LAV/HTLVⅢ病毒巳通过美国生产的Ⅷ因子制剂传入中国。     

二氧化硫熏气对小麦叶片中1-氨基环丙烷-1-羧酸、1-(丙二酰氨基)环丙烷-1-羧酸含量的影响及与乙烯产生的关系

在SO_2熏气9h过程中,小麦叶片中乙烯先上升,约6h达高峰,后下降;ACC含量则随熏气时间的延长而上升。停止熏气,乙烯继续下降,ACC含量也明显降低。MACC含量从熏气3h后不断上升,脱离接触后仍继续增加。6-BA预处理对SO_2引起的乙烯和ACC上升有促进作用,但对MACC含量无明显影响。SO_2熏气提高了乙烯形成酶活性。6-BA预处理对SO_2伤害有保护作用。对逆境乙烯的产生与调节作用进行了讨论。